Honeywell 9782 Series manual Performing Calibration Trim, Materials and procedure, Concentration M

Calibration

8.4 Performing Calibration Trim

Introduction

For most applications entering the cal factor for each cell will achieve satisfactory system performance. However, it is possible to perform a calibration trim procedure in which the Analyzer/Controller and cell combination are used to measure a reference solution of known conductivity; the reading of the Analyzer/Controller is adjusted to match.

The same procedure can be used to adjust the Analyzer/Controller’s reading while the cell is in the process, if a reference instrument is used to determine the process conductivity. In this case, the process fluid becomes the “reference solution”.

Materials and procedure

To perform calibration trim using a standard reference solution, follow the instructions in Table 8-3.

Materials required are:

∙A reference solution of known conductivity near the point of interest, with the temperature controlled (or measured and compensated) to within ± 1 °C. Conductivities of potassium

chloride solutions are provided in Table 8-2. Solutions must be prepared with high-purity de-ionized, CO2-free water, and dried potassium chloride.

∙A container for the reference solution, large enough to immerse the cell to measuring depth.

∙De-ionized water to rinse the cell.

Table 8-2 Conductivity of Potassium Chloride Solutions at 25 °C

Concentration M*

0.001

0.005

0.01

0.02

0.05

Conductivity (microsiemens

per cm)

147.0

717.8

1,413

2,767

6,668

* M = Molarity; 1M = 74.555g potassium chloride per liter of solution

7/99 9782 Series Conductivity/Resistivity Analyzer/Controller - Operator’s Manual 8-5